This invention relates to an electromagnetically actuated spring clutch and, more particularly, to a clutch of the same general type as disclosed in Wahlstedt U.S. Pat. No. 4,263,995.
In such a clutch, a helical torque-transmitting clutch spring carried by a rotating input hub is caused to wrap down onto an axially adjacent output hub by means of an applied magnetic field. Such clutches are useful in the controlled intermittent operation of numerous mechanical devices such as the paper feeders of office copying machines.
The magnetic field is created by an electromagnet having a coil which, when excited, produces magnetic flux. The flux threads through the components of the clutch and serves to attract a control collar axially into engagement with a pole piece of the magnet. Such engagement causes the control collar to rotate slightly relative to the input hub of the clutch and to cause the spring to wrap down on the output hub so as to couple the two hubs for rotation in unison.